package offer;

import java.util.Scanner;

/**
 * @author cyt
 * @create 2020-05-19 17:32
 */
public class T8 {
    static int ans = 0;
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        if (a >= 36) {
            System.out.println(0);
            return;
        } else {
            System.out.println(JumpFloor(a));
        }
    }
    public static int JumpFloor(int target) {
        dfs(target);
        return ans;
    }

    static void dfs(int cnt) {
        if (cnt < 0) {
            return;
        }
        if (cnt == 0) {
            ans++;
            return;
        }
        dfs(cnt - 1);
        dfs(cnt - 2);
    }
}
